Hi everyone,
I'm trying to use function vcov to extract the covariance matrix from a GAMLSS object. But I'm getting some strange errors and I was hoping someone could help me out? Vcov works with the same model for lm and glm objects, but not gamlss objects. I've searched various help sites to no avail. Its very possible the reason is that vcov failed though, since I got the following error message in the summary of the model "summary: vcov has failed, option qr is used instead" In which case I was wondering if anyone could help me out by explaining how I can find the covariance matrix equivalent without using vcov? The code and error messages I got for vcov are as follows. > vcov(paper_size_type_income) The following object(s) are masked _by_ .GlobalEnv : child id paper Error in gamlssNonLinear(family = RG, data = paper3, y = paper, mu.formula = paper ~ : NAs in y - use na.omit() I then try using na.omit and I get a different error message (even though there are no NA's in the data set, I checked using table(paper3$paper, exclude=NULL)) > temp <- gamlss(na.omit(paper)~size + type + income, family=RG, data=paper3) GAMLSS-RS iteration 1: Global Deviance = 1160.816 GAMLSS-RS iteration 2: Global Deviance = 1159.963 GAMLSS-RS iteration 3: Global Deviance = 1159.951 GAMLSS-RS iteration 4: Global Deviance = 1159.951 > vcov(temp) The following object(s) are masked _by_ .GlobalEnv : child id paper Error in inteprFormula.default(formula, .envir = envir, .start = start.v, : covariates in formulae with unknowns must not be factors check sizecovariates in formulae with unknowns must not be factors check typecovariates in formulae with unknowns must not be factors check income > thanks Chris Howden Marketing Scientist For all your Analysis, Modelling, Experimental Design and Training needs (mobile) 0410 689 945 (fax / office) (+618) 8952 7878 tall.chr...@yahoo.com.au [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.